Total electric power to grid [MWe]

Dear Paul,
First of all, thank you very much for answering my questions. I am simulating a CSP plant, but I don't know what the difference is between "Total electric power to grid [MWe]" and "Electricity to grid [kW]".
In my case, I have to:
System power generated [kW] = Electricity to grid [kW]
But why
Total electric power to grid [MWe]> Electricity to grid [kW]?
What is the difference? and why is one greater than the other?
Thanks once again,
Best regards,
Francisco

Hi Francisco,

The "Total electric power to grid" is the output of the power cycle before the "System Availability" losses on the System Control page are applied. By default, there is a 4% system availability loss, which explains the difference between the variables you list.

I agree that this is confusing. We will fix this for a future version of SAM.

Best regards,
Paul.

Paul,
In the same vein, can we get complete definitions of the following ?  Also, are they kWdc or kWac ?

System power before grid curtailment (kW)
System power before grid interconnect (kW)
System power generated (kW)

Hi Mike,

Those three values are all in AC kW. "Grid curtailment" and "grid interconnect" refer to the inputs on the Grid Limits page. The outputs are intended to show when power is lost due to either of those.

Grid curtailment limits apply in individual time steps, so the input is an array of hourly or subhourly time series values.

The grid interconnection limit is a single value that applies throughout the year. Its input is a single value.

These inputs are intended to model operational limits to the system's output imposed by external factors such as grid outages and grid capacity limits.

Here's how SAM applies those values in each time step:

1. Calculate the output of the system, called "system power before grid interconnect."

2. Apply the interconnection limit to calculate "system power before grid curtailment."

3. Apply curtailment to calculate "system power generated," which represents the power delivered to the grid.

The result is that "system power generated" in a given time step should never exceed either grid curtailment in that time step or the interconnection limit. If both a grid interconnection limit and curtailment apply in a given time step, system power generated should be equal to or less than the smaller of the two.

Best regards,
Paul.